Letter sheet



W. E. SWIFT Aug. 15, 1939.

LETTER SHEET Filed July is, 1935 2 Sheets-Sheet 1 Inven+or-;

u S m O 6 H d% r Aug. 15, 1939.

W. E. SWIFT LETTER SHEET Filed July 18, 1935 2 Sheets-Sheet 2 unumd a. sw-ln Patented Aug. 15, 1939 UNITED STATES PATENT OFFICE LETTER SHEET Application July 18, 1935, Serial No. 32,065

3 Claims.

The present invention relates to letter sheets of the type that are adapted to be folded after being written upon to form closures for mailing, which letter sheets have heretofore required the moistening of gummed portions, after folding, in order to seal the same.

According to the present invention, there is provided an improved letter sheet in which the necessity for moistening any portion is entirely eliminated by coating certain portions of the sheet with an adhesive having the prop rty of sticking to itself upon non-moistened contact, so that when the sheet is folded to bring its adhesive coated areas into overlying relation, sealing immediately results. The invention also contemplates the manufacture of such sheets in an em tremely economical manner, and the above and 'other advantageous features of the invention will hereinafter more fully appear from the following description with reference to the accompanying drawings, in which:

Fig. 1 shows one side of a letter sheet embodying the invention.

Fig. 2 shows the opposite side of the sheet of Fig. 1.

Fig. 3 illustrates the initial folding of the sheet to form a closure.

Fig. 4 illustrates the final folding of the sheet preparatory to sealing.

Fig. 5 shows the closure formed from the folded sheet completely sealed.

Fig. 6 shows a modified form of letter sheet.

Figs. 7 and 8 illustrate folding of the sheet of Fig. 6 to form a closure.

Fig. 9 shows the closure formed from the folded sheet completely sealed.

Fig. 10 illustrates a manner of cutting the sheets to reduce wastage.

Like reference characters refer to like parts in the different figures.

Referring first to Figs. 1 and 2, a sheet I generally rectangular in form provides a flap 2 extending along one edge thereof and spaced score lines 3, 3 extending transversely across the sheet from the extremities of the flap 2. A third score line 4, extends longitudinally of the sheet I at right angles to the score lines 3 and substantially midway of the sheet, and a fourth score line 5 extends along the junction of the flap 2 with the sheet I.

The flap 2 is provided with adhesive 6 covering substantially the entire area of the flap on the side of the sheet shown in Fig. 1, and the opposite side of the sheet provides a correspondingly shaped area of adhesive 1 extending partially along the opposite longitudinal edge of the sheet securely than has heretofore been possible with from the fiap 2, as shown in Fig. 2. This side of the sheet also provides spaced bands of adhesive 8, 8 extending in parallel relation outside of the score lines 3, 3. The adhesive 6, 1 and 8 is of such a character that any portion thereof will '5 adhere to another portion, upon non-moistened contact, although it will not adhere to the material of the sheet l. Preferably, the adhesive is applied in the form of a dispersed rubber solution, or as natural or compounded latex, the in- :10 vention also contemplating the use of other similar dry-sealing adhesives in the form of thermoplastics, such as arclor resins or galyptols, either alone or in combination.

When it is desired to convert the sheet I into a closure, after the side shown in Fig. 1 has been written on, the sheet is first folded from opposite ends along the score lines 3, 3 to bring the folded portions into overlying relation with the body of the sheet, as shown in Fig. 3, with the written matter completely covered. This folding disposes the bands of adhesive 3, 8 along opposite edges of the partially folded sheet, so that when, the sheet is next folded along the score line 4, as shown in Fig. 4, opposed portions of the adhesive 8 are disposed in overlying relation. Thereafter, application of pressure to the edges of the folded sheet causes immediate adhesion between the engaged adhesive coated areas along the edges and the conversion of the sheet into a complete closure having all the capabilities of an ordinary envelope.

Sealing of the envelope of Fig. 4 is completed by folding over the flap 2 along the score line 5 to bring its adhesive 6 into engagement with the 3 adhesive 7, which adhesive 7 has been disposed just below the score line 5 by the previous folding operation. Pressure applied to the folded over flap 2 then completely seals the envelope more ordinary letter sheets provided with gumming that requires moistening. In addition, the sealing at the ends of the closure between the overlying bands of adhesive 8 effectively prevents the envelope from being partially opened, as would otherwise be possible in the absence of the adhesive 8.

Referring now to Fig. 6, there is shown another form of letter sheet 9 providing a flap ID, with spaced parallel lines of scoring l l, H and l2, I2 extending at right angles to each other across the sheet. The flap I0 is covered with adhesive I3 of the same character as the adhesive previously described with reference to sheet I, and the opposite side of the sheet 9 provides an area of dry-sealing adhesive l4 corresponding to the shape and size of the flap adhesive l3.

When it is desired to convert the sheet 9 into a closure, after writing thereon, the sheet is folded from opposite ends along the score lines II, II to bring the folded portions into overlying relation with the remainder of the sheet, as shown in Fig. '7, with the written matter completely covered. 7 The doubled portion of the sheet is then folded twice, first along the lower score line I2 and then along the upper score line l2, as shown in Fig. 8, which folding serves to reverse the posi tion of the adhesive HI, previously on the back of the sheet. Since this adhesive l4 lies between the score lines I2, and the second folding brings the lower score line I2 in register with a score line. l5 between the flap IO- and the body of the sheet, the adhesive I4 is now disposed opposite the adhesive l3. Sealing of the closure thus formed by folding the sheet 9 is then completed by merely folding over the flap ID to bring'its adhesive l3 into contact with the adhesive 14, followed bythe application of pressure, the completely sealed closure then appearing as shown 'With a minimum of wastage.

both transverselyand longitudinally of its axis,

whereby two series of letter sheets are formed as the cutting proceeds, with their interlocking flaps cut from the continuous band of adhesive l3a. In this way, sheets such as are shown in Fig. 6 can be formed from the web IS with an absolute minimum of wastage, and. obviously sheets such as are shown in Fig. 1 can be formed in substantially the same manner.

From the foregoing, it is apparent that by the present invention'there are provided improved letter sheets which may be readily folded to form complete closures and then sealed, without the necessity of moistening thesealingmedium.

I claim:

l. A mailing closure made from a rectangular sheet providing a flap projecting from one edge thereof, with said flap and the opposite side of the sheet provided with corresponding areas of dry-sealing adhesive, said sheet being foldable in a series of steps to form a closure in which substantially equal areas of the folded sheet are disposed in overlying relation, with said adhesive areas disposed on opposite sides of a line along which said flap is foldable to bring said. adhesive areas into engagement to seal the closure.

"2. A mailing closure made from a rectangular sheet providing a flap projecting from one edge thereof, with said flap and the opposite side of the sheet provided with corresponding areas of dry-sealing adhesive, said sheet being foldable to first form a partial closure, and then to form a complete closure in which substantially equal areas of the folded sheet are disposed in overlying relation, with said adhesive areas disposed on opposite sides of a line along which said flap is finally foldable tobring said areas into engagement to seal the closure. 1

3. A letter sheet in the form of a rectangular blank providing a flap projecting from one edge thereof, with said flap and the opposite side of the blank provided with corresponding areas of dry-sealing adhesive, said blank being-foldable in a series of steps to form a closure in. which sub- 'stantially equal rectangular areas of the folded blank are disposed in overlying relation,.with said adhesive areas disposed on opposite sides of a line along which said flapis finally foldable to bring said adhesive areas into engagement to 1 seal the closure.

' ,WILLARD E. SWIFT; 

